Allergies: Who, What, When and Why

al’ lêr gy, noun - An abnormal immune response (an allergic response) to a non-harmful trigger (an allergen).

Exposure to allergens does not produce allergy symptoms in non-allergic individuals but causes mild to severe symptoms in an allergic person. These symptoms may include sneezing; watery, itchy, red eyes; a runny nose, a scratchy throat or cough. Some allergy sufferers have more symptoms involving the skin. Dry, red, itchy patches of skin called eczema can be caused by allergies. A severe allergic reaction may be expressed as hives, swelling of the lips, eyes or extremities. Life threatening allergic reactions occur when airways become swollen shut or when a rapid drop in blood pressure (shock) occurs.

There are two factors that determine if a person will have allergies: their genetic background, and their exposure to allergens. Allergies run in families. If one parent has allergies, there is about a 30 percent chance that their children will have allergies. If both parents have allergies, the likelihood goes up to about 70 percent that each child will develop allergies. The genetic background provides the potential to develop allergies, the environment provides the allergen trigger. The warm, moist climate of Houston and the Gulf Coast ensure that there are plenty of allergens year round to trigger allergy symptoms.

Anything that enters the body is potentially capable of producing an allergic response. In general, however, the most common allergic triggers are pollens (from grasses, trees, weeds), mold spores, dust mites (microscopic organisms found in house dust), insect venoms, animal danders and foods. Only two percent of the population has actual food allergies, but allergic reactions to foods are often severe and are potentially life threatening. Tobacco smoke, perfume, hair spray and the components of air pollution are generally not allergens, but their presence can make existing allergy symptoms worse.

Some allergens have a defined season. Ragweed, for example, pollinates during the fall and is a common cause of allergic symptoms from September through Thanksgiving. Other allergens have less defined seasons and their levels will fluctuate throughout the year.

Allergy-Related Conditions

Allergy sufferers are more likely to also suffer from the following conditions:

		Frequent Sinus Infections
		Ear Infections
		Asthma and Bronchitis
		Eczema
		Sleep Disorders
		Migraine Headaches

Children with allergies are sometimes mistakenly diagnosed with ADHD due to their allergy symptoms interfering with their ability to concentrate in school.

Environmental Allergies

Your home, school or workplace may contain substances that can cause an allergic reaction. These environmental substances include dust or dust mites, animal dander (mostly cats), mold spores, mildew or pollen. While pollen allergies usually occur in certain seasons, these other substances can cause allergy problems all year round.

While avoidance is the best solution in most cases, some causes of symptoms, such as pollen, molds, and dust mites, cannot be eliminated. Exposure can be reduced, however, by environmental control measures prescribed by your allergist.

When it comes to allergies, living in Houston makes treatment harder because the true allergy to dust mites, mold or pollen is superimposed on the non-allergic effects of the pollution, ozone and humidity. Many patients say they feel great when they travel elsewhere, only to have symptoms come roaring back as soon as they return. So, if you're going to live in Houston because of your job, or because this is where your loved ones are, then successfully treating allergies may require you to be a bit more aggressive. That means paying equal attention to avoiding dust mites or mold that you're allergic to, avoiding non-allergic triggers (e.g., cigarette smoke, perfume, etc), and seeking medical help.

Dust and Dust Mites

The following information is courtesy of Mission Allergy:

Dust mites are microscopic creatures that live in pillows, mattresses, blankets, carpets, and other soft materials. They are often thought of as insects, but are actually tiny arachnids, relatives of spiders and ticks. They do not live on people, but live near them. Their food is the dead skin scales that we all shed every day.

Dust mites avoid the light, and require at least 50% relative humidity to survive. They are therefore plentiful in soft materials, such as pillows, mattresses, and blankets, where they can burrow into the fabric to get away from the light. Beds provide the warmth, darkness, high humidity, and shed skin scales that mites crave, and they are the source of the biggest mite exposure for most of us. A mattress may contain over a million dust mites. A female mite lays about 60 eggs in her lifetime. Each mite lives for about 80 days, during which time it produces one thousand allergy-causing waste particles.

Live mites themselves are not inhaled. Rather, it is the waste particles that they have produced, and the body fragments of dead dust mites, that become airborne, are inhaled and cause allergy symptoms. This is because mites do not live in the air, but are burrowed in soft materials. Mite waste particles become briefly airborne when one walks on a carpet, sits on an upholstered chair, places one's face on a pillow, makes a bed, or otherwise disturbs the soft materials where the dust mites are living.

Ragweed Pollen

After a long Houston summer, we're all ready for cool evenings. But when nighttime temperatures drop below 70 degrees, and humidity drops below 70%, ragweed starts to grow. Ragweed is the main source of allergic misery for those who suffer in September and October. Ragweed will continue to make pollen until early November unless we get an early freeze.

Interestingly, several foods cross-react with ragweed. If you are allergic to ragweed, you may experience itching or tingling of the lips or tongue when you eat cantaloupe, watermelon or bananas while ragweed pollen counts are high. Interestingly, by cooking the related food, heat will alter the structure of the antigen, usually making it non-allergenic. Drinking chamomile tea may cause a similar reaction.

Ragweed puts out more pollen in the mornings than in the evenings, so if you're allergic to it, save outside activities for late afternoon or after a heavy rain, when pollen levels are lower.

We've been waiting all summer to roll down the windows in our car, but if you're allergic to ragweed, this is asking for trouble. Take advantage of the filtering system in your car's HVAC system to keep symptoms in check. If you have an indoor dog that goes outside to play for a while, consider giving him/her a bath; dog fur has a static charge which acts as a transport mechanism to bring in all sorts of pollen.

Ragweed is named for the raggedy shape of its leaves. It's not a very pretty plant; still, what it lacks in beauty, it makes up for in potency. One ragweed plant can put out over one billion grains of pollen! Its scientific name, Ambrosia, was the delicious food eaten by the mythical Greek gods to make them live forever.

Remember, if you're on one of those preventative steroid nose sprays (e.g., Nasonex, Rhinocort, or Nasacort), start it soon so it will be working when ragweed pollen hits its peak.

Food Allergies

Often, patients come in telling us what foods they are allergic to on the basis of allergy testing done years before. It’s quite possible that they are not allergic to those foods at all. Allergy testing is very accurate when we test for dust mites, mold, and pollen. But it’s less accurate when we test for foods. Years ago, many allergists, even those board certified by the American Board of Allergy and Immunology, would tell patients to avoid foods on the basis of skin test results alone. The most reliable way to confirm a food allergy is with a food challenge. This test involves giving a capsule to a patient that contains either the food that they suspect or a placebo. To ensure the objectivity and validity, the patient (and often the doctor) doesn’t know which capsule they receive.

Reactions can range from immediate itching or swelling of the lips and/or tongue, to hives, coughing, and wheezing. These usually happen within a few minutes after eating the food, sometimes up to an hour. But some true food allergies cause stomach cramping and diarrhea hours later. Unfortunately, there are no safe and effective forms of allergy shots or allergy drops for food allergy at this time. Food allergies can be life-threatening, especially if one is allergic to peanuts, shellfish, or tree nuts. Besides avoiding these foods, the doctor should prescribe an injector device with epinephrine (adrenaline) to be available at all times. Make sure that the one you buy has at least 12 months left until it expires. You often get the freshest at 24-hour pharmacies. Still, if anaphylaxis occurs and all you have is an expired device, good research shows that it’s still worthwhile using it.

A careful distinction must be made between “food allergy” and “food intolerance.” Many people have lactose intolerance, which causes gastrointestinal symptoms upon eating milk products. Other examples of food intolerance include headaches from drinking wine or a runny nose from eating spicy foods.

If you are egg allergic, it is recommended you get your flu shot in a doctor's office; if you have a severe egg allergy, or had a serious reaction after getting a flu shot, it is recommended you get the flu shot in an allergist's office. Remember, there is definitely a risk to not getting immunized – influenza-related illness in the U.S. averages 200,000 hospitalizations per year and 10,000 deaths per year. Read more about egg allergy and flu vaccine...

Eye allergies

You don’t have itchy, watery eyes, and you don’t sneeze or get runny/stuffy nose.

Maybe your eyes are just heavy or tired, or it feels like there is sand stuck in your eyes. That could also be allergies. There’s no law that says every allergic patient has to itch or sneeze. Avoiding what you’re allergic to is the best place to start. Wear sunglasses when cutting the grass or exercising outdoors to reduce the amount of pollen that gets in your eyes. When indoors, eyes glued to that computer screen, force yourself to blink once in a while. Eyelids make pretty good windshield wipers. Extended-wear contact lenses often worsen allergies because pollen and mold spores stick to the lens. Hard lenses, or daily disposable soft contacts may be a better choice if you have allergies.

Over the counter eye drops can be helpful, but can also make things worse. Start out with moisturizing eye drops like Refresh, GenTeal, or other artificial tears. If those aren’t enough, the best non-prescription eye drop for itching/watering is Alaway (ketotifen). But like other (e.g., Claritin, Zyrtec, Benadryl) antihistamines, it may dry things out; not good if you already have dry eyes. Avoid Visine and Clear Eyes; products that “get the red out” temporarily shrink the blood vessels. But repeated use of these makes the redness worse. The latest, greatest prescription eye drops (Pataday, Patanol and Bepreve) don’t work better than Alaway, but they have much less burning and stinging.

Keep drops in the refrigerator. They feel more soothing when they are cold.

Even if you don’t have nose symptoms, the nasal steroids Veramyst and Nasonex help eye allergies. They reduce inflammation of the little tube that connects the eyes to the nose.

When these measures don’t help, allergy shots to make you less allergic to pollen, mold or dust mites often work. But make sure you get your allergy shots from a doctor board-certified in allergy and immunology — not some bootleg allergist who may not dose the shots correctly. The main reason allergy shots don’t work is because they are not dosed correctly. Dr. Alnoor Malick and Dr. Sunil Saraf ensure that our recipes for allergy shots comply with the latest guidelines.

After all, we Special Eyes (specialize) in allergies.

Other Allergies

Some people have allergic reactions to other sources, including:

		Aerosols
		Air fresheners
		Air pollution
		Aspirin
		Cat dander
		Christmas trees
		Drugs
		Eggs
		Garden plants
		Insect Stings
		Iodine dye
		Perfumes
		Ragweed pollen
		Tobacco Smoke
		Wood Smoke

Some factors can make allergies feel worse, including:

		Cold Air
		Humidity
		Wind